Vulcan55

Every time I try to use the feather tool on something (And some blurs) the entire picture becomes distorted and fuzzy, but it never used to do this before. Example: Before shot. You can clearly see the tranpsarency, but there are some light pixels around the outside and I need it to look good against a dark bg. After: I put a black layer behind it and tried to feather, but this happened. I'm not sure what to do. Maybe someone knows how to help? Thank you.